Wang Lingyan, Li Shitao, Jungalwala Firoze B
Department of Neurobiology, E. K. Shriver Center, University of Massachusetts Medical School, Waltham, Massachusetts 02452, USA.
J Neurosci Res. 2008 May 1;86(6):1254-66. doi: 10.1002/jnr.21578.
The receptor for advanced glycation end products (RAGE) plays a crucial role in several disease processes, such as diabetes, inflammation, and neurodegeneration. In this article we report multiple roles of RAGE in neuronal differentiation and neurite outgrowth. In retinoic-induced P19 embryonic carcinoma stem cells, silencing the expression of RAGE by RNA interference (RNAi) blocked differentiation of the P19 cells into neuronal cells and enhanced the formation of vimentin-positive fibroblast-like cells. RAGE knockdown inhibited retinoic acid-induced activation and blocked nuclear translocation of NF-kappaB, suggesting RAGE regulates activation of NF-kappaB. RAGE was also shown to be involved in survival of P19 cells during retinoic acid differentiation. Additionally, knockdown of RAGE strongly inhibited neurite outgrowth in retinoic acid-differentiated P19 cells, indicating that RAGE is required for neurite outgrowth of differentiated P19 cells. Retinoic acid-treated P19 cells activated GTPases, Rac1, and Cdc42. This activation of the GTPases was inhibited in RAGE-knockdown cells. In primary cerebellar granule neurons, the knockdown of RAGE also inhibited neurite outgrowth. In these cells, overexpression of dominant-negative forms of Rac1 and Cdc42 inhibited neurite outgrowth, whereas overexpression of constitutively active forms of Rac1 and Cdc42 in RAGE-deficient neurons restored neurite outgrowth, indicating that RAGE mediated neurite outgrowth through the Rac1/Cdc42 pathway. This is the first report on the role of RAGE in cell lines and primary neurons, as determined by RNAi knockdown.
晚期糖基化终末产物受体(RAGE)在多种疾病过程中发挥关键作用,如糖尿病、炎症和神经退行性变。在本文中,我们报告了RAGE在神经元分化和神经突生长中的多种作用。在视黄酸诱导的P19胚胎癌细胞中,通过RNA干扰(RNAi)沉默RAGE的表达可阻断P19细胞向神经元细胞的分化,并增强波形蛋白阳性成纤维细胞样细胞的形成。RAGE基因敲低抑制视黄酸诱导的激活并阻断NF-κB的核转位,提示RAGE调节NF-κB的激活。RAGE还被证明参与视黄酸分化过程中P19细胞的存活。此外,RAGE基因敲低强烈抑制视黄酸分化的P19细胞中的神经突生长,表明RAGE是分化的P19细胞神经突生长所必需的。视黄酸处理的P19细胞激活了GTP酶、Rac1和Cdc42。这种GTP酶的激活在RAGE基因敲低的细胞中受到抑制。在原代小脑颗粒神经元中,RAGE基因敲低也抑制了神经突生长。在这些细胞中,Rac1和Cdc42的显性负性形式的过表达抑制了神经突生长,而在RAGE缺陷神经元中组成型活性形式的Rac1和Cdc42的过表达恢复了神经突生长,表明RAGE通过Rac1/Cdc42途径介导神经突生长。这是关于通过RNAi敲低确定RAGE在细胞系和原代神经元中的作用的首次报道。